The Optical Transport Hierarchy (OTH) is a transport technology for the Optical Transport Network (OTN) developed by the International Telecommunication Union (ITU). The main implementation of OTH is described in two recommendations by the Telecommunication Standardization section of the ITU (ITU-T), including:
Recommendation G.709/Y.1331, entitled “Interfaces for the optical transport network”, February 2012, with an Erratum 1 (January 2014), a Corrigendum 1 (October 2012), an Amendment 1 (October 2012), an Amendment 2 (October 2013), an Amendment 3 (May 2014), a Corrigendum 2 (January 2015), and an Amendment 4 (January 2015).
Recommendation G.872, entitled “Architecture of optical transport networks”, October 2012, with an Amendment 1 (November 2013).
Work toward OTN implementations for speeds beyond 100 Gbps, so-called B100G, is ongoing. Those familiar with OTN will recognize the OTN signal hierarchy, including OPU, ODU, and OTU signals or frames. The addition of “C” in the signal or frame types in the hierarchy, for OPUC, ODUC, and OTUC, represents “100” for 100 Gbps (hereinafter “G” is used as a short form for “Gbps”) and higher speeds. An index “n”, for OTUCn for instance, indicates a multiple of 100G. In one possible B100G implementation, an OTUC signal has a provisionable rate in increments of 100G. OTUC1=100G, OTUC2=200G, and so on, or more generally OTUCn=n×100G.